CA1075888A - Flooding with micellar systems affected by cosurfactants - Google Patents
Flooding with micellar systems affected by cosurfactantsInfo
- Publication number
- CA1075888A CA1075888A CA255,509A CA255509A CA1075888A CA 1075888 A CA1075888 A CA 1075888A CA 255509 A CA255509 A CA 255509A CA 1075888 A CA1075888 A CA 1075888A
- Authority
- CA
- Canada
- Prior art keywords
- cosurfactant
- micellar
- dispersion
- viscosity
- water
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K8/00—Compositions for drilling of boreholes or wells; Compositions for treating boreholes or wells, e.g. for completion or for remedial operations
- C09K8/58—Compositions for enhanced recovery methods for obtaining hydrocarbons, i.e. for improving the mobility of the oil, e.g. displacing fluids
- C09K8/584—Compositions for enhanced recovery methods for obtaining hydrocarbons, i.e. for improving the mobility of the oil, e.g. displacing fluids characterised by the use of specific surfactants
Abstract
FLOODING WITH MICELLAR SYSTEMS AFFECTED BY COSURFACTANTS
ABSTRACT OF THE DISCLOSURE
Improved oil recovery by flooding subterranean forma-tions with micellar dispersions comprised of hydrocarbon, water, cosurfactant, electrolyte, and surfactant is obtained by adding water-soluble alcohols to the micellar dispersion to obtain lower viscosity micellar systems or adding rela-tively water-insoluble alcohols to obtain higher viscosi-ties. By adjusting the viscosity of the micellar system, better mobility control can be obtained during the flooding process.
ABSTRACT OF THE DISCLOSURE
Improved oil recovery by flooding subterranean forma-tions with micellar dispersions comprised of hydrocarbon, water, cosurfactant, electrolyte, and surfactant is obtained by adding water-soluble alcohols to the micellar dispersion to obtain lower viscosity micellar systems or adding rela-tively water-insoluble alcohols to obtain higher viscosi-ties. By adjusting the viscosity of the micellar system, better mobility control can be obtained during the flooding process.
Description
1~751 3~8 BACKGR~rJND OF THE INVENTION
Field of the Invention _ ; This invention relates to injecting a micellar dispersion into a subterranean formation and displacing it toward a - production means in fluid communication with the formation to recover crude oil therethrough.
Description of the Prior Art .
~ icellar dispersions are useful for recovering crude oil from subterranean reservoirs, e.g. U.S. Patent Nos.
3,254,714; 3,275,0/5; 3,506,070i 3,~97,00~; 3,613,786;
3,734,1BS; 3,740,343; 3,827,496; and other patents defining surfactant systems and assigned to Marathon Oil Company, Esso Production Research Co., Shell Oil Company, Union Oil Company, Mobil Oil Company, Texaco Oil Company, etc. The prior art generally teaches that the micellar dispersion is injected into the oil-bearing formation followed by a mobility control buffer and th~n a water drive to displace previously injected slugs toward a production well to recover crude oil thcrethrough.
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1 The prior art generally teaches that the viscosity of a
Field of the Invention _ ; This invention relates to injecting a micellar dispersion into a subterranean formation and displacing it toward a - production means in fluid communication with the formation to recover crude oil therethrough.
Description of the Prior Art .
~ icellar dispersions are useful for recovering crude oil from subterranean reservoirs, e.g. U.S. Patent Nos.
3,254,714; 3,275,0/5; 3,506,070i 3,~97,00~; 3,613,786;
3,734,1BS; 3,740,343; 3,827,496; and other patents defining surfactant systems and assigned to Marathon Oil Company, Esso Production Research Co., Shell Oil Company, Union Oil Company, Mobil Oil Company, Texaco Oil Company, etc. The prior art generally teaches that the micellar dispersion is injected into the oil-bearing formation followed by a mobility control buffer and th~n a water drive to displace previously injected slugs toward a production well to recover crude oil thcrethrough.
'~ ' .~ , 750021~
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~:1'75138~
1 The prior art generally teaches that the viscosity of a
2 micellar dispersion can be controlled by the water eoncentra-
3 tion--see U.S. 3,254,71~; that cosurfactant can be added to
4 a soluble oil to achieve proper viscosity--U.S. 3,~77,511;
S and that water-soluble salts can be added to control the 6 viscosity--see U.S. 3,330,3~3. Also, -the prior art has 7 recognized that high molecular weight polymers can be 8 added to the micellar dispçrsion to increase the viscosity 9 and that the hydrocarbon used in making up the dispersion ean influence the viscosity--see U.S. 3,412,791.
11 Designing the micellar dispersion to have the desired 12 viseosity is important in secondary and tertiary oil 13 reeovery processes. If vlseosity is too low, mobility will 14 be too high and the slug will unstably and ineffieiently displaee oil and will eause "viseous fingering". If, on 16 the other hand, slug viscosity is too high, either the mobility 17 buffer, i.e. aqueous polymer solution, intended to drive 18 the slug will finger into the slug, or excessive polymer 19 eoncentrations within the buffer will be required. Since polymer is expensive, the latter alternative is eeonomieally 21 unattractive. By selecting the proper type and eoncentration 22 of eosurfaetant, slug viseosity ean be adjusted so that the slug will neither finger into the oil that it is intended 24 to displaee, nor will excessive polymer be required.
In summary, the prior art has recognized that the 26 viscosity of the mieellar dispersions ean be affeeted by 27 hydroearbon, eleetrolyte, polymer, water, and aleohols;
28 these aleohols, in most cases, have been water-soluble alcohols.
.~. i '. ' 107588~
S~ RY O F T~IE INVF.NTION
~ pplicants have (llscovered that the vlscoslty of mlcellar disperslons can be ad~usted by incorporating a relatively water-insolllble cosurfactant to obtain a high viscosity or incorporating a water-soluble cosurfactant with the micellar dispersion to obtain a low viscosity. That is, by increasing the hydrophilicy of the cosurfactant, the viscosity of the micellar dispersion is lowered.
In one particular aspect the present invention provides in a process for recovering hydrocarbon from a subterranean formation having at least one injection means in fluid communication with at least one production means and wherein a micellar dispersion of predetermined viscosity and comprised of water, hydrocarbon, cosurfactant(s), surfactant, and optionally electrolyte is injected into the formation and displaced toward the production means to recover hydrocarbon therethrough, the improvement comprising admixing with the micellar dispersion a more hydrophilic cosurfactant than the cosurfactant within the dispersion to obtain a low viscosity micellar dispersion or incorporating a less hydrophilic cosurfactant than the cosurfactant within the micellar dispersion to obtain a higher viscosity, said more or less hydrophilic cosurfactant being a Cl to about C2 5 organic compound or a mixture of Cl to about C25 organic compounds, and thereafter injecting the dispersion of a desired viscosity into the formation and displacing it toward the production means to recover hydrocarbon therethrough.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 shows the influence of p-pentanol and p-hexanol on the same micellar dispersion composition (defined in Example I). The p-hexanol has very little water solubility and obtains high viscosities whereas the p-pentanol is more .: $
~ jl/\~;(~, 3-:
. 3, ~0'~58~
hyclrophi.l:ic nncl obta:ins lowcr vi.scosities.
Figure 2 shows thc effect of four different alcohols on the composition deEined in Example II. Although the same viscosity can be obtained using any of the four alcohols shown in this figure, a broad range of vlscosities is available as a Eunction oE alcohol concentration. For example, slug viscosity as low as 20 cp. or as high as 150 cp. can be obtained with the least water-soluble alcohol nonyl phenol.
The maximum obtainable viscosity with a slightly more water-soluble p-hexanol is about 100 cp. Although a viscosity of about 70 cp. can be obtained using either 2-hexanol or n-pentanol, experience has shown that oil recovery efficiency drops off at the low end of the alcohol .
: 20 :' ~ 3a--~, `" "' ' .~ . . , .
., : . . . .
1~758B13 1 concentration range. ~s a practical matter, -the maximum 2 viscosities obtainable usincJ 2-hexanol and n-pentanol and 3 still obtain eEfective oil-displacing characteristics is 4 about 38 to 30 cp, respectively.
.~
. 7 The term "micellar dispersion" as used herein is meant to include miceilar solutions, microemulsions, "transparent 9 emulsions", hydrous soluble oils, micellar sys-tems con-taining lamellar micelles, etc. These systems can be oil-11 external or water-external, they can act li~e they are 12 either oil-external or water-ex-ternal or both, and they can 13 also be in an "intermediate region" between a "classically"
14 oil-external micellar system and a "classically" water-external micellar system. However, all of the systems, 16 regardless of the externali-ty properties, are thermodynamically 17 stable and optically clear; however, color bodies within the 18 different components can prevent the transmission of light.
19 The micellar dispersions are composed of hydrocarbon, water, petroleum sulfonate, cosurfactant, and optionally 21 electrolyte. Additional component(s) can be added if 22 desirable to impart properties to the micellar dispersion.
23 However, these components must be compatible with the other 24 components of the dispersion and not impart adverse properties to the system.
26 Examples of the components useful with -the micellar 27 dispersion are defined wikhin the patents mentioned in 28 the "Description of the Prior Art".
29 The surfactant can be anionic, nonionic, or cationic, or mixtures thereof Preferably, it is a monovalent 31 cation containing petroleum sulfonate obtained by sulfonating :: ' 1075~8~
1 a fraction oE crude oil, e.g. gas oil, or whole or topped 2 crude oil and thereafter neutralizing with ammonium hydroxide 3 or sodium hydroxide. Desirably, the petroleum sulfonate has 4 an a~erage equivalent weighl within the range of about 350 to about 525 and more preferably about 390 to about 460 and most preferably about 400 to about 450. The petroleum 7 sulfonate can contain unreacted hydrocarbon and salts (herein-after defined as electrolytes).
9 The hydrocarbon is typically crude oil, a fraction thereof, unreacted vehicle oil within the surfactant, 11 synthesized hydrocarbon, mixtures thereof, or like materials.
12 Water within the micellar dispersion can be distilled 13 water, fresh water, or water containing a moderate amount of 14 salts. Typically, the water contains about 5 to about 50,000 ppm of TDS (total dissolved solids). Preferably, the 16 water does not contain sufficient amounts of multi-valent 17 cations that will displace or exchange a significant amount of 18 the cations on the surfactant.
19 Useful electrolytes include water-soluble inorganic salts, inorganic bases, inorganic acids, or mixtures thereo~.
21 Typically, the salts are reaction by-products from the 22 preferred petroleum sulfonate, e.g. ammonium sulfate, ammonium 23 sulfite, sodium sulfate, sodium sulfite, etc., but the 24 electrolytes can be added or blended with other electrolytes in the aqueous phase of the micellar dispersion mixture.
26 The cosurfactant, also known as a semi-polar organic 27 compound, cosolubilizer, stabilizing agent~ is an organic 28 compound(s) containing l to about 25 or more carbon atoms ~9 and more preferably 3 to about l~ carbon atoms. It can be an alcohol, amide, amino compound, ester, aldehyde, ketone, 31 complexes thereof, or a compound containing one or more of , .` .
~ . ' ~75888 amido, hydroxy, bromo, chloro, carbonato, mercapto, oxo, 2 oxy, carbonyl, or like cJroups, or mixtures thereof. Specific 3 examples include isopropanol, butanol, amyl alcohols, 4 hexanols, octanols, decyl alcohols, alkyl aryl alcohols such as n-nonyl phenol and p-nonyl phenol, 2-butoxyhexanol, 6 alcoholic liquors such as fusel oil, mixed isomer5 of pri~ary 7 amyl or hexyl alcohols such as UCAR-HCO (marketed by Union 8 Carbide Company, N.Y., N.Y.~, blends of C12, C13, C14, C15, 9 etc. linear primary alcohols such as Neodol alcohols (marketed by Shell Chemical Co.), ethoxylated alcohols such as alcohols 11 containing 4 to about 16 carbon atoms that are ethoxylated 12 and optionally sulfated, hydrogenated hydrocarbons such as 13 hydrogenated croton oil, amidized hydrocarbons, and like 14 materials. The preferred cosurfactant is an alcohol which can be primary, secondary or tertiary alcohol or mixtures 16 thereof and can optionally be ethoxylated and/or sulfated.
17 Concentration of the components within the micellar 18 dispersion vary depending upon the particular component and 19 the particular properties desired of the micellar dispersion.
Typically, the concentration is about 4 to abou-t 86% and 21 preferably about 5 to about 50% and more preferably about 6 22 to about 20% hydrocarbon, about 10 to about 92% and preferably 23 about 40 to about 91% and more preferably about 60 to about 24 90% water, about 4 to about 20% or more and preferably about 25 6 to about 16% and more preferably about 7 to about 12% o~
26 surfactant; about 0.01 to about 20% and preferably about 27 0.05 to about 10% and more preferably about 0.1 to about 3~
28 of cosurEactant, and about 0.001 to about 10% and preferably 29 about 0.01 to about 7.5% and more preferably about 0.25 to about 5% of electrolyte.
31 The micellar dispersion is injected into the formation 12~
...~., .
' ~C~75~3~38 1 in volume amounts of 1 to about 50% or more, and preferably 2 abo~lt 4 to about 15% FPV (formation pore volume). This is 3 preferably followed by a mobility buffer, preferably an 4 aqueous solution containin~ a water-soluble polymer which imparts permeability reduction to the formation and/or 6 viscosity-increasing properties to -the aqueous solution--si 7 examples of volume amounts include about 10 ~o abou~ 200%
FPV or more and preferably about 50 to about 150% FPV, and 9 more preferably about 60 to about 100% FPV. A water drive is injected to displace the micellar dispersion and the 11 mobility buffer toward a production well in fluid communi-12 cation with the formation to recover crude oil through said 13 production well.
14 A micellar dispersion will accept or "take-up" so much of a particular cosurfactant while remaining phase-stable.
16 This cosurfactant range is obtained by titrating the micellar 17 dispersion with the cosurfactant. The micellar dispersion 18 may go through a viscosity maximum ~generally characteristic 19 of micellar systems containing greater than about 60% water) and then, upon further titration~ the viscosity will decrease.
21 The micellar dispersions are preferably on the "right side"
22 of the viscosity maximum to obtain optimum oil recoveries.
23 More preferably, after the micellar dispersion goes through 24 the viscosity maximum, cosurfactant titration is continued until the desired viscosity is obtained for flooding a 26 particular formation. A micellar dispersion containing less 27 than about 60% water may not pass through a viscosity maximum 28 upon cosurfactant titration. Instead, the viscosity may pass 29 through a minimum as illustrated in Figure 2. With Figure 2 type systems, it is preferred that the system be at the 31 minimum viscosity or to its "right side" of the viscosity 750021-~ _7_ I
..;~ , ...
~ S888 1 curve to obtain optim~l oil recovery.
2 The desired viscosity will depend upon the combined 3 mobility of the crude oil and connate water within the 4 formation to be flooded, the design mobility of the mobility buffer, the "life" o~ the flooding project, and in general, . the overall design mobility and desired "pay-out" and economics i 7 of the flooding project.
The viscosity of the micellar dispersion will depend 9 upon the components and concentration of the components.
For a given micellar dispersion, the hydrophilicy or lack 11 thereof of the cosurfactant influences the viscosity of the 12 micellar dispersion. That is, a hydrophilic cosurfactant 13 obtains low viscosities whereas a less hydrophilic cosurfactant 14 obtains higher viscosities. Thus, for a given micellar dispersion, one will add a hydrophilic cosur~actant to 16 obtain a lower viscosity. Examples of preferred cosur-17 factants which exhibit an increase in hydrophilicy as the below numbers increase include the following:
19 1) p-octanol 2~ p-heptanol 21 3) p-hexanol 22 4) p-pentanol 23 5) p-bu-tanol 24 6) isopropyl alcohol 7) ethanol 26 8) methanol 27 For a given primary, secondary or tertiary alcohol, or other 28 functional groups on the cosurfactant, the higher the 29 molecular weight, the less hydrophilic the cosurfactant generally is. However, having two or more functional groups 31 on -the cosurfactant molecule generally increases the hydro-io 750021-A -8-' il[3'7588~3 philicy of ~he mol~cule alld as .~iuch can hclVe an "overridirlcJ"
influence over the molecular ~eight to cleternlinc the hydro--philicy thereof.
Generally speakincJ, it is desired that the micellar dispersion be designed to have a greater reciprocal mobility at reservoir conditions than the combined reciprocal mobility of the formation fluids, specifically crude oil and connate water, and gas if presen-t in the formation~ By following Applicants' teachings, one can design the micellar dispersion to initially contain the desired cosurfactant for optimum viscosity design, or one can add a desired cosurfactant to a micellar dispersion containing a cosurfactant to adjust the viscosity thereof to the desired viscosity.
Working Examples The following examples are presented to teach specific embodi~ents of the invention Unless otherwise specified, all percents are based on volume and measurements of the properties are obtained at ambient temperature, i e 22-23C.
EXAMPLE I
A micellar dispersion composition, before alcohol addition, is obtained by mixing 11.7% of an ammonium petroleum sulfonate having an average equivalent weight of 420 and being 62 weight percent active sulfonate and obtained by sulfonating a gas oil with SO3, 22.8% oE a crude oil having an API gravity of 37~ and a viscosity of 7-9 cp, and 65.5%
water containing 400 ppm of TDS and 10,000 ppm of (NH4)SO4, Total water concentration of the dispersion, including water from the sulfonate, is 70~ by weight To this mixture there ; 30 is added p-pentanol or p~hexanol The alcohol concen-tration ~ and the resulting viscosities of the micellar dispersion are _g_ bm : \ J
.:: .
.,.: . , .
',' ~ ' , ',,', ,.' ,',': .. ..
i~S8~38 1 illustrated in Figurc 1.
2 It is evident from Figure 1 that p-pentanol imparts a lower 3 viscosity than p-hexanol. Thus, for a given micellar dispersion 4 composition, and for similar alcohols, the alcohol having the greater solubility in water obtains a lower viscosity.
7 A micellar dispersion composition before alcohol addikion 8 is obtained by mixing 10% ~f an ammonium petroleum sulfonate which is 61 weight percent active sulfonate and has an average equivalent weight of 440, 40% of hydrocarbon which 11 is 60% of the crude oil defined in Example I and 40% of 12 heavy naphtha, 50~ of water which contains 400 ppm of TDS and 13 3900 ppm of ammonium sulfate. The total water concentration 14 of this slug, including water from the sulfonate, is 54.5% by weight. To separate samples of this c~mposition is added 16 four different cosurfactants, i.e. nonyl phenol! p-hexanol, 17 2-hexanol, and n-pentanol. The titration of these compositions 18 and the viscosities thereof are illustrated in Figure 2.
19 It is not intended that this invention be limited by the specifics taught within the above examples. Rather, all 21 equivalents obvious to those skilled in -the art are intended 22 to be incorporated within the scope of the invention as 24 defined with the specification and appended claims.
` 30 :- .
S and that water-soluble salts can be added to control the 6 viscosity--see U.S. 3,330,3~3. Also, -the prior art has 7 recognized that high molecular weight polymers can be 8 added to the micellar dispçrsion to increase the viscosity 9 and that the hydrocarbon used in making up the dispersion ean influence the viscosity--see U.S. 3,412,791.
11 Designing the micellar dispersion to have the desired 12 viseosity is important in secondary and tertiary oil 13 reeovery processes. If vlseosity is too low, mobility will 14 be too high and the slug will unstably and ineffieiently displaee oil and will eause "viseous fingering". If, on 16 the other hand, slug viscosity is too high, either the mobility 17 buffer, i.e. aqueous polymer solution, intended to drive 18 the slug will finger into the slug, or excessive polymer 19 eoncentrations within the buffer will be required. Since polymer is expensive, the latter alternative is eeonomieally 21 unattractive. By selecting the proper type and eoncentration 22 of eosurfaetant, slug viseosity ean be adjusted so that the slug will neither finger into the oil that it is intended 24 to displaee, nor will excessive polymer be required.
In summary, the prior art has recognized that the 26 viscosity of the mieellar dispersions ean be affeeted by 27 hydroearbon, eleetrolyte, polymer, water, and aleohols;
28 these aleohols, in most cases, have been water-soluble alcohols.
.~. i '. ' 107588~
S~ RY O F T~IE INVF.NTION
~ pplicants have (llscovered that the vlscoslty of mlcellar disperslons can be ad~usted by incorporating a relatively water-insolllble cosurfactant to obtain a high viscosity or incorporating a water-soluble cosurfactant with the micellar dispersion to obtain a low viscosity. That is, by increasing the hydrophilicy of the cosurfactant, the viscosity of the micellar dispersion is lowered.
In one particular aspect the present invention provides in a process for recovering hydrocarbon from a subterranean formation having at least one injection means in fluid communication with at least one production means and wherein a micellar dispersion of predetermined viscosity and comprised of water, hydrocarbon, cosurfactant(s), surfactant, and optionally electrolyte is injected into the formation and displaced toward the production means to recover hydrocarbon therethrough, the improvement comprising admixing with the micellar dispersion a more hydrophilic cosurfactant than the cosurfactant within the dispersion to obtain a low viscosity micellar dispersion or incorporating a less hydrophilic cosurfactant than the cosurfactant within the micellar dispersion to obtain a higher viscosity, said more or less hydrophilic cosurfactant being a Cl to about C2 5 organic compound or a mixture of Cl to about C25 organic compounds, and thereafter injecting the dispersion of a desired viscosity into the formation and displacing it toward the production means to recover hydrocarbon therethrough.
BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 shows the influence of p-pentanol and p-hexanol on the same micellar dispersion composition (defined in Example I). The p-hexanol has very little water solubility and obtains high viscosities whereas the p-pentanol is more .: $
~ jl/\~;(~, 3-:
. 3, ~0'~58~
hyclrophi.l:ic nncl obta:ins lowcr vi.scosities.
Figure 2 shows thc effect of four different alcohols on the composition deEined in Example II. Although the same viscosity can be obtained using any of the four alcohols shown in this figure, a broad range of vlscosities is available as a Eunction oE alcohol concentration. For example, slug viscosity as low as 20 cp. or as high as 150 cp. can be obtained with the least water-soluble alcohol nonyl phenol.
The maximum obtainable viscosity with a slightly more water-soluble p-hexanol is about 100 cp. Although a viscosity of about 70 cp. can be obtained using either 2-hexanol or n-pentanol, experience has shown that oil recovery efficiency drops off at the low end of the alcohol .
: 20 :' ~ 3a--~, `" "' ' .~ . . , .
., : . . . .
1~758B13 1 concentration range. ~s a practical matter, -the maximum 2 viscosities obtainable usincJ 2-hexanol and n-pentanol and 3 still obtain eEfective oil-displacing characteristics is 4 about 38 to 30 cp, respectively.
.~
. 7 The term "micellar dispersion" as used herein is meant to include miceilar solutions, microemulsions, "transparent 9 emulsions", hydrous soluble oils, micellar sys-tems con-taining lamellar micelles, etc. These systems can be oil-11 external or water-external, they can act li~e they are 12 either oil-external or water-ex-ternal or both, and they can 13 also be in an "intermediate region" between a "classically"
14 oil-external micellar system and a "classically" water-external micellar system. However, all of the systems, 16 regardless of the externali-ty properties, are thermodynamically 17 stable and optically clear; however, color bodies within the 18 different components can prevent the transmission of light.
19 The micellar dispersions are composed of hydrocarbon, water, petroleum sulfonate, cosurfactant, and optionally 21 electrolyte. Additional component(s) can be added if 22 desirable to impart properties to the micellar dispersion.
23 However, these components must be compatible with the other 24 components of the dispersion and not impart adverse properties to the system.
26 Examples of the components useful with -the micellar 27 dispersion are defined wikhin the patents mentioned in 28 the "Description of the Prior Art".
29 The surfactant can be anionic, nonionic, or cationic, or mixtures thereof Preferably, it is a monovalent 31 cation containing petroleum sulfonate obtained by sulfonating :: ' 1075~8~
1 a fraction oE crude oil, e.g. gas oil, or whole or topped 2 crude oil and thereafter neutralizing with ammonium hydroxide 3 or sodium hydroxide. Desirably, the petroleum sulfonate has 4 an a~erage equivalent weighl within the range of about 350 to about 525 and more preferably about 390 to about 460 and most preferably about 400 to about 450. The petroleum 7 sulfonate can contain unreacted hydrocarbon and salts (herein-after defined as electrolytes).
9 The hydrocarbon is typically crude oil, a fraction thereof, unreacted vehicle oil within the surfactant, 11 synthesized hydrocarbon, mixtures thereof, or like materials.
12 Water within the micellar dispersion can be distilled 13 water, fresh water, or water containing a moderate amount of 14 salts. Typically, the water contains about 5 to about 50,000 ppm of TDS (total dissolved solids). Preferably, the 16 water does not contain sufficient amounts of multi-valent 17 cations that will displace or exchange a significant amount of 18 the cations on the surfactant.
19 Useful electrolytes include water-soluble inorganic salts, inorganic bases, inorganic acids, or mixtures thereo~.
21 Typically, the salts are reaction by-products from the 22 preferred petroleum sulfonate, e.g. ammonium sulfate, ammonium 23 sulfite, sodium sulfate, sodium sulfite, etc., but the 24 electrolytes can be added or blended with other electrolytes in the aqueous phase of the micellar dispersion mixture.
26 The cosurfactant, also known as a semi-polar organic 27 compound, cosolubilizer, stabilizing agent~ is an organic 28 compound(s) containing l to about 25 or more carbon atoms ~9 and more preferably 3 to about l~ carbon atoms. It can be an alcohol, amide, amino compound, ester, aldehyde, ketone, 31 complexes thereof, or a compound containing one or more of , .` .
~ . ' ~75888 amido, hydroxy, bromo, chloro, carbonato, mercapto, oxo, 2 oxy, carbonyl, or like cJroups, or mixtures thereof. Specific 3 examples include isopropanol, butanol, amyl alcohols, 4 hexanols, octanols, decyl alcohols, alkyl aryl alcohols such as n-nonyl phenol and p-nonyl phenol, 2-butoxyhexanol, 6 alcoholic liquors such as fusel oil, mixed isomer5 of pri~ary 7 amyl or hexyl alcohols such as UCAR-HCO (marketed by Union 8 Carbide Company, N.Y., N.Y.~, blends of C12, C13, C14, C15, 9 etc. linear primary alcohols such as Neodol alcohols (marketed by Shell Chemical Co.), ethoxylated alcohols such as alcohols 11 containing 4 to about 16 carbon atoms that are ethoxylated 12 and optionally sulfated, hydrogenated hydrocarbons such as 13 hydrogenated croton oil, amidized hydrocarbons, and like 14 materials. The preferred cosurfactant is an alcohol which can be primary, secondary or tertiary alcohol or mixtures 16 thereof and can optionally be ethoxylated and/or sulfated.
17 Concentration of the components within the micellar 18 dispersion vary depending upon the particular component and 19 the particular properties desired of the micellar dispersion.
Typically, the concentration is about 4 to abou-t 86% and 21 preferably about 5 to about 50% and more preferably about 6 22 to about 20% hydrocarbon, about 10 to about 92% and preferably 23 about 40 to about 91% and more preferably about 60 to about 24 90% water, about 4 to about 20% or more and preferably about 25 6 to about 16% and more preferably about 7 to about 12% o~
26 surfactant; about 0.01 to about 20% and preferably about 27 0.05 to about 10% and more preferably about 0.1 to about 3~
28 of cosurEactant, and about 0.001 to about 10% and preferably 29 about 0.01 to about 7.5% and more preferably about 0.25 to about 5% of electrolyte.
31 The micellar dispersion is injected into the formation 12~
...~., .
' ~C~75~3~38 1 in volume amounts of 1 to about 50% or more, and preferably 2 abo~lt 4 to about 15% FPV (formation pore volume). This is 3 preferably followed by a mobility buffer, preferably an 4 aqueous solution containin~ a water-soluble polymer which imparts permeability reduction to the formation and/or 6 viscosity-increasing properties to -the aqueous solution--si 7 examples of volume amounts include about 10 ~o abou~ 200%
FPV or more and preferably about 50 to about 150% FPV, and 9 more preferably about 60 to about 100% FPV. A water drive is injected to displace the micellar dispersion and the 11 mobility buffer toward a production well in fluid communi-12 cation with the formation to recover crude oil through said 13 production well.
14 A micellar dispersion will accept or "take-up" so much of a particular cosurfactant while remaining phase-stable.
16 This cosurfactant range is obtained by titrating the micellar 17 dispersion with the cosurfactant. The micellar dispersion 18 may go through a viscosity maximum ~generally characteristic 19 of micellar systems containing greater than about 60% water) and then, upon further titration~ the viscosity will decrease.
21 The micellar dispersions are preferably on the "right side"
22 of the viscosity maximum to obtain optimum oil recoveries.
23 More preferably, after the micellar dispersion goes through 24 the viscosity maximum, cosurfactant titration is continued until the desired viscosity is obtained for flooding a 26 particular formation. A micellar dispersion containing less 27 than about 60% water may not pass through a viscosity maximum 28 upon cosurfactant titration. Instead, the viscosity may pass 29 through a minimum as illustrated in Figure 2. With Figure 2 type systems, it is preferred that the system be at the 31 minimum viscosity or to its "right side" of the viscosity 750021-~ _7_ I
..;~ , ...
~ S888 1 curve to obtain optim~l oil recovery.
2 The desired viscosity will depend upon the combined 3 mobility of the crude oil and connate water within the 4 formation to be flooded, the design mobility of the mobility buffer, the "life" o~ the flooding project, and in general, . the overall design mobility and desired "pay-out" and economics i 7 of the flooding project.
The viscosity of the micellar dispersion will depend 9 upon the components and concentration of the components.
For a given micellar dispersion, the hydrophilicy or lack 11 thereof of the cosurfactant influences the viscosity of the 12 micellar dispersion. That is, a hydrophilic cosurfactant 13 obtains low viscosities whereas a less hydrophilic cosurfactant 14 obtains higher viscosities. Thus, for a given micellar dispersion, one will add a hydrophilic cosur~actant to 16 obtain a lower viscosity. Examples of preferred cosur-17 factants which exhibit an increase in hydrophilicy as the below numbers increase include the following:
19 1) p-octanol 2~ p-heptanol 21 3) p-hexanol 22 4) p-pentanol 23 5) p-bu-tanol 24 6) isopropyl alcohol 7) ethanol 26 8) methanol 27 For a given primary, secondary or tertiary alcohol, or other 28 functional groups on the cosurfactant, the higher the 29 molecular weight, the less hydrophilic the cosurfactant generally is. However, having two or more functional groups 31 on -the cosurfactant molecule generally increases the hydro-io 750021-A -8-' il[3'7588~3 philicy of ~he mol~cule alld as .~iuch can hclVe an "overridirlcJ"
influence over the molecular ~eight to cleternlinc the hydro--philicy thereof.
Generally speakincJ, it is desired that the micellar dispersion be designed to have a greater reciprocal mobility at reservoir conditions than the combined reciprocal mobility of the formation fluids, specifically crude oil and connate water, and gas if presen-t in the formation~ By following Applicants' teachings, one can design the micellar dispersion to initially contain the desired cosurfactant for optimum viscosity design, or one can add a desired cosurfactant to a micellar dispersion containing a cosurfactant to adjust the viscosity thereof to the desired viscosity.
Working Examples The following examples are presented to teach specific embodi~ents of the invention Unless otherwise specified, all percents are based on volume and measurements of the properties are obtained at ambient temperature, i e 22-23C.
EXAMPLE I
A micellar dispersion composition, before alcohol addition, is obtained by mixing 11.7% of an ammonium petroleum sulfonate having an average equivalent weight of 420 and being 62 weight percent active sulfonate and obtained by sulfonating a gas oil with SO3, 22.8% oE a crude oil having an API gravity of 37~ and a viscosity of 7-9 cp, and 65.5%
water containing 400 ppm of TDS and 10,000 ppm of (NH4)SO4, Total water concentration of the dispersion, including water from the sulfonate, is 70~ by weight To this mixture there ; 30 is added p-pentanol or p~hexanol The alcohol concen-tration ~ and the resulting viscosities of the micellar dispersion are _g_ bm : \ J
.:: .
.,.: . , .
',' ~ ' , ',,', ,.' ,',': .. ..
i~S8~38 1 illustrated in Figurc 1.
2 It is evident from Figure 1 that p-pentanol imparts a lower 3 viscosity than p-hexanol. Thus, for a given micellar dispersion 4 composition, and for similar alcohols, the alcohol having the greater solubility in water obtains a lower viscosity.
7 A micellar dispersion composition before alcohol addikion 8 is obtained by mixing 10% ~f an ammonium petroleum sulfonate which is 61 weight percent active sulfonate and has an average equivalent weight of 440, 40% of hydrocarbon which 11 is 60% of the crude oil defined in Example I and 40% of 12 heavy naphtha, 50~ of water which contains 400 ppm of TDS and 13 3900 ppm of ammonium sulfate. The total water concentration 14 of this slug, including water from the sulfonate, is 54.5% by weight. To separate samples of this c~mposition is added 16 four different cosurfactants, i.e. nonyl phenol! p-hexanol, 17 2-hexanol, and n-pentanol. The titration of these compositions 18 and the viscosities thereof are illustrated in Figure 2.
19 It is not intended that this invention be limited by the specifics taught within the above examples. Rather, all 21 equivalents obvious to those skilled in -the art are intended 22 to be incorporated within the scope of the invention as 24 defined with the specification and appended claims.
` 30 :- .
Claims (7)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In a process for recovering hydrocarbon from a subterranean formation having at least one injection means in fluid communication with at least one production means and wherein a micellar dispersion of predetermined viscosity and comprised of water, hydrocarbon, cosurfactant(s), surfactant, and optionally electrolyte is injected into the formation and displaced toward the production means to recover hydrocarbon therethrough, the improvement comprising admixing with the micellar dispersion a more hydrophilic cosurfactant than the cosurfactant within the dispersion to obtain a low viscosity micellar dispersion or incorporating a less hydrophilic cosurfactant than the cosurfactant within the micellar dispersion to obtain a higher viscosity, said more or less hydrophilic cosurfactant being a C1 to about C25 organic compound or a mixture of C1 to about C25 organic compounds, and thereafter injecting the dispersion of a desired viscosity into the formation and displacing it toward the production means to recover hydrocarbon there-through.
2. The process of Claim 1 wherein the dispersion contains about 4 to about 20% surfactant, about 4 to about 86% of hydrocarbon, about 10 to about 92% water and about 0.01 to about 20% cosurfactant.
3. The process of Claim 1 wherein the dispersion contains about 0.001 to about 10% electrolyte.
4. The process of Claim 1 wherein the surfactant is a monovalent cation-containing petroleum sulfonate.
5. The process of Claim 1 wherein said more hydrophilic or said less hydrophilic cosurfactant is preselected to impart the desired viscosity to the micellar dispersion.
6. The process of Claim 1 wherein the cosurfactant is an alcohol.
7. The process of Claim 1 wherein the electrolyte is a water-soluble inorganic salt, inorganic base, inorganic acid or mixture thereof.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US60356175A | 1975-08-11 | 1975-08-11 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1075888A true CA1075888A (en) | 1980-04-22 |
Family
ID=24415964
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA255,509A Expired CA1075888A (en) | 1975-08-11 | 1976-06-23 | Flooding with micellar systems affected by cosurfactants |
Country Status (10)
| Country | Link |
|---|---|
| JP (1) | JPS5222504A (en) |
| AU (1) | AU1677176A (en) |
| BR (1) | BR7604820A (en) |
| CA (1) | CA1075888A (en) |
| DE (1) | DE2629232C2 (en) |
| FR (1) | FR2321037A1 (en) |
| GB (1) | GB1520563A (en) |
| IN (1) | IN145458B (en) |
| NL (1) | NL7607349A (en) |
| SU (1) | SU668622A3 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9328243B2 (en) | 2009-03-02 | 2016-05-03 | Harris Corporation | Carbon strand radio frequency heating susceptor |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR2445854B2 (en) * | 1977-07-08 | 1981-06-12 | Elf Aquitaine | MICROEMULSIONS FOR USE AS CEMENT "SPACERS" |
Family Cites Families (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1249190B (en) * | 1967-09-07 | Marathon Oil Company, Findlay, Ohio (V. St. A.) | Process for secondary oil removal from oil reservoirs | |
| US3163214A (en) * | 1961-11-13 | 1964-12-29 | Pure Oil Co | Solvent-waterflood oil recovery process |
| DE1558988B1 (en) * | 1967-01-23 | 1971-04-15 | Marathon Oil Co | Use of an essentially water-insoluble co-surface-active agent for the production of storage oil |
| US3497006A (en) * | 1967-12-26 | 1970-02-24 | Marathon Oil Co | High water content oil-external micellar dispersions |
| US3477511A (en) * | 1968-09-13 | 1969-11-11 | Marathon Oil Co | Process for the recovery of petroleum using soluble oils |
| US3916997A (en) * | 1973-09-13 | 1975-11-04 | Marathon Oil Co | Oil recovery with high conductivity micellar systems |
| AR205218A1 (en) * | 1975-01-20 | 1976-04-12 | Mc Graw Edison Co | IMPROVED ELECTRICAL CAPACITOR AND MANUFACTURING METHOD |
| JPS5184062A (en) * | 1975-01-21 | 1976-07-23 | Nippon Electric Co |
-
1976
- 1976-06-18 IN IN1083/CAL/76A patent/IN145458B/en unknown
- 1976-06-22 GB GB25904/76A patent/GB1520563A/en not_active Expired
- 1976-06-23 CA CA255,509A patent/CA1075888A/en not_active Expired
- 1976-06-25 DE DE2629232A patent/DE2629232C2/en not_active Expired
- 1976-07-02 NL NL7607349A patent/NL7607349A/en not_active Application Discontinuation
- 1976-07-16 JP JP51084064A patent/JPS5222504A/en active Granted
- 1976-07-21 SU SU762385531A patent/SU668622A3/en active
- 1976-07-23 BR BR7604820A patent/BR7604820A/en unknown
- 1976-08-06 FR FR7624049A patent/FR2321037A1/en not_active Withdrawn
- 1976-08-11 AU AU16771/76A patent/AU1677176A/en not_active Expired
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9328243B2 (en) | 2009-03-02 | 2016-05-03 | Harris Corporation | Carbon strand radio frequency heating susceptor |
Also Published As
| Publication number | Publication date |
|---|---|
| BR7604820A (en) | 1977-08-02 |
| JPS5222504A (en) | 1977-02-19 |
| AU1677176A (en) | 1978-02-16 |
| GB1520563A (en) | 1978-08-09 |
| SU668622A3 (en) | 1979-06-15 |
| FR2321037A1 (en) | 1977-03-11 |
| JPS562597B2 (en) | 1981-01-20 |
| DE2629232C2 (en) | 1982-07-29 |
| DE2629232A1 (en) | 1977-02-24 |
| NL7607349A (en) | 1977-02-15 |
| IN145458B (en) | 1978-10-14 |
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